To produce a frosted coating made of aqueous (water-soluble type or water-dispersed type) polyurethane, it was ordinary practice to:add a silica frosting agent suspended in water to polyurethane, apply it to the surface of an article such as a glass bottle, and let it dry and cure.
In this case, in the suspension comprising water and a silica frosting agent, the latter settles with time, which may cause phase separation. In order to prevent this problem, it was necessary to add a commercially available thickening agent or surface-active agent.
But if a thickening agent or surface-active agent is added in an amount sufficient to prevent the separation and settling of the silica frosting agent in the suspension, the aqueous polyurethane itself will thicken. This lowers its flow and formability as a coating agent. On the other hand, if the use of a thickening agent and surface-active agent is restricted, the silica frosting agent will aggregate in the polyurethane, thus lowering the physical properties of the coating such as resistance to scuff.
An object of this invention is to provide a frosting agent in which fine particles of silica are suspended in an aqueous solvent in a suitable manner, which obviates the above problems, which does not lower the flow and formability of the aqueous polyurethane as a binder nor the resistance to scuff of the coating.